Conventionally, in an electrical system of an automobile, many vehicle-mounted components, such as electrical junction boxes including a junction box and a fuse box and a connector holder in which a connector provided in a terminal end of a wire harness is held, have been employed. For example, as disclosed in JP 2011-10493A (Patent Document 1), these vehicle-mounted components are provided with a box main body for accommodating and holding an internal circuit body, a connector, and the like and a cover member for covering an opening portion of the box main body.
Incidentally, for example, as disclosed in JP 2010-108849A (Patent Document 2), there are cases where such a vehicle-mounted component is attached to a vehicle body panel by inserting the vehicle-mounted component through a through hole provided in the vehicle body panel and fixing the fixing portions protruding on the peripheral wall portion of the box main body with bolts to the peripheral edge portion of the through hole of the vehicle body panel.
However, due to the recent demands for miniaturization and densification of vehicles, the installation space of the vehicle-mounted components is also limited, and it is sometimes difficult to pass the vehicle-mounted component through the through hole of the vehicle body and arrange it on the outer side of the vehicle body panel. Furthermore, the protrusion allowance of the vehicle-mounted component to the inside of the vehicle body panel is often restricted, and there are also cases where it is not possible to adopt a structure for stably attaching the vehicle-mounted component to the vehicle body panel via a separate bracket. Accordingly, to realize stable attachment to the vehicle body panel within a limited space, the structure of the box main body becomes complicated and there is a concern that attaching the box main body and the cover member to each other will be difficult.